1. Field of the Invention
The invention relates to an electron beam inspection method and particularly relates to an electron beam inspection optimization.
2. Description of Related Art
As line width continue to shrink in an IC manufacturing process, control and monitoring of the critical dimension (CD) for the fabrication become more and more important. From the aspect of nano-scale semiconductor technology, it becomes more difficult to accurately inspect defects on the surface structure of a chip.
Currently, an E-beam inspection tool is used to inspect the chip surface structure. However, E-beam inspection is an inspection method of high resolution for small inspected area. The inspection may usually take hours or tens of days depending on the size of the inspected area.
Therefore, various methods have been proposed recently to reduce the inspected points so as to shorten the time required for electron beam inspection. However, they still require a lot of time in order to obtain the chip image and find the defects.